Battery powered sensors and utility meters are now commonplace. Battery powered meters and sensors may be designed to only be read by onsite inspection, or they may include a transmitter to allow transmission of sensed data to a remote location. Remote wireless sensor networks may include sensor nodes spread out over a home, office building, or factory to help with energy management, comfort enhancement, security, diagnostics, and other applications.
Battery life is a key consideration when implementing a wireless sensor network as many battery-operated sensors may be in inaccessible locations. Additionally, changing batteries in a large number of sensor nodes poses huge operational and environmental costs. Radio power of these wireless nodes is one source of battery drain. RF standards such as ZigBee are popular in low data rate, low power applications. ZigBee and other low power RF standards use MAC and PHY layers defined by IEEE 802.15.4. An amendment to 802.15.4, called 802.15.4e uses a duty-cycled MAC (media access control) to reduce radio power consumption.
Another source of battery drain for a sensor is the operation of the sensor itself, which typically must be activated at a high repetition rate. Some types of sensor device may use an inductive component to monitor a physical parameter. To perform measurement, a current is produced in the inductor of the sensor. This is normally done with a short voltage pulse applied to a primary inductor to induce a response in a secondary inductor that provides an indication of the physical parameter being sensed.
Other features of the present embodiments will be apparent from the accompanying drawings and from the detailed description that follows.